1993 Fiscal Year Final Research Report Summary
Study on nonlinear effects in propagation of frequency-chirped laser pulse in atomic laser isotope separation
| Project/Area Number |
04452327
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Nuclear engineering
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| Research Institution | Osaka University |
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Principal Investigator |
IZAWA Yasukazu Osaka University, ILE, Professor, レーザー核融合研究センター, 教授 (10029316)
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| Co-Investigator(Kenkyū-buntansha) |
SAKABE Shuji Faculty of Engineering, Assistant Professor, 工学部, 講師 (50153903)
NIKI Hideaki Fukui University, Associate Professor, 工学部, 助教授 (00135758)
NISHIHARA Katsunobu ILE, Professor, レーザー核融合研究センター, 教授 (40107131)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Uranium enrichment / Near-resonant interaction / Nonlinear effects in laser beam propagation / Frequency-chirped pulse / Pulse compression / Self-phase modulation |
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| Research Abstract |
In atomic vapor laser isotope separation of uranium, the laser beams propagate through the uranium atomic vapor for a long distance in reacting with U^<235>N on resonance and also U^<238>N in near-resonance. The near-resonant interaction will modify the laser pulse shape and the carrier frequency during the propagation. We have developed a simulation code named CEALIS-P which treats the atomic excitation dynamics and the laser beam propagation simultaneously and investigated the effect of near-resonant interaction on the separation characteristics numerically and experimentally. The following results have been obtained successfully.
1)In the near-resonant interaction, the modification of pulse shape and the propagation velocity of frequency chirped laser pulse greatly depend on the direction of frequency sweep. In uranium enrichment system, the positively frequency chirped laser pulse in compressed in pulse width and is decreased in propagation velocity.
2)The dependences of these modification on the frequency sweep width, the weep rate, the incident laser intensity and the atomic density were analyzed and the optimum laser condition were discussed to obtain the efficient excitation and high enrichment.
3)In samarium atomic vapor the pulse compression and the pulse delay of frequency chirped pulse due to near-resonant effects have been measured experimentally. Good agreements between the experiments and simulations lead the usefulness of simulation for the design of uranium enrichment plant by lasers.
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